1. Field of the Invention
This invention relates to a separable fastener of the hook-and-loop type, male-and-female type, hook-to-hook type or other type (hereinafter referred to generally as "separable fastener") and more particularly to a separable fastener which can be appropriately used as a fastening means for disposable products.
2. Description of the Prior Art
The conventional separable fastener generally comprises a substrate having the reverse side thereof coated with a layer of an organic solvent type adhesive agent, the surface of the adhesive layer being coated with a release paper. The separable fastener thus constructed needs to be stripped of the release paper before it is applied to a given object. Prior to use, therefore, it must spend time and labor for the separation of the release paper and suffer the separated release paper to be discarded as waste and, as a result, take part in the recent problem of disposal of plastics waste.
Disposable products such as diapers which are made of water-soluble resins have been developed recently. Such disposable products as are made of water-soluble resin are dissolved and disintegrated when they are left immersed in water. They are, therefore, discarded safely in flush toilet and enabled to contribute to the solution of the problem of waste disposal. The base cloth of a diaper, for example, is tied and untied generally by means of such fastening means as a separable fastener. Since these fastening means are made of a water-insoluble resin, the diaper to which the fastening means is left attached cannot be discarded in the flush toilet. The fastening means such as a separable fastener is attached to the base cloth with an organic solvent type adhesive agent. Even after the fastening means has been removed from the base cloth, therefore, the component of the adhesive agent is suffered to remain on the base fabric and mingle in the waste water in the flush toilet and consequently form one cause for the problem of waste water disposal and the pollution of river water.
In recent years, the problem of disposal of plastics waste has come to attract attention from the viewpoint of conservation of the earth's environment and the demand for the development of a technology for waste disposal has been gaining in enthusiasm. As one of the targets of the development, the biodegradable plastics to be incorporated in the circulation of matter in the natural world have been arresting attention.
The biodegradable resinous materials which are disintegrated on exposure to the microbial action in soil or in water are known in various kinds such as (a) the microbial fermentative production type, (b) starch alloy type, (c) chemical synthesis type, and (d) polylactic acid type. The development of these biodegradable resinous materials for use in such containers as bottles, cups, and trays besides wrapping films and bags is now under way.
No case of applying a biodegradable resin or a water-soluble resin to the separable fastener which is the object of the present invention, however, has been known to the art.